Stabilized-frequency oscillator arrangement



H. CHIREIX Feb. 11, 1941.

S TABILI ZED-FREQUEN CY 05 C ILLATOR ARRANGEMENT Filed May 21, 1938 I NV EN TOR. HE? CHIRE/X W M ATTORNEY.

Patented Feb. 11, 1941 2,231,155

UNITED STATES PATENT @FFME STABILIZED -FR EQUENCY SCILLATOR ARRANGEMENT Henri Chireix, Paris, France,- assignor to Compagnie Gencrale De Telegraphic Sans Fil, a corporation of France Application May 21, 1938, Serial No. 209,202 In France June 1, 1937 8 Claims. (01. 250-36) The outstanding feature of this arrangement It will be noted that all of these elements occur is that the said circuit is not in need of being in the so-called Hartley oscillator arrangement essentially of the low-loss or low-damped kind and which has here been chosen for the sake of arguthat, therefore, the same may be of reduced ment and example. However, instead of condimensions and may preferably be confined inside necting directly with the cathode (ground) a a thermostat. suitable point of the inductance coil 2, the said The invention is based upon an appreciation point is connected through a capacity of large of the fact that, if in addition to the normal value 8; and his will brin a out no han e i excitation on the control grid (which excitation the properties of the circuit organization.

10 is in phase opposition to the output potential), NOW, incorporated in the latter are the follow- 10 there i impressed on t same grid or upon ing elements, and this constitutes the characternoth r grid supplementary cit ti hich istic feature of the invention: First, an oscillatory is in quadrature to the normal excitation, varicircuit consisting of an inductance comprising ations of the ensuing frequency will be occasioned. three constituent p namely and the If, then, the value of the excitation in quadrature D labeled 9 being i coup ing relationship with 15 or its effect is made to be a function of the inthe inductance 2 as indicated in e drawing, stantaneous frequency itself, it is possible to and 0f the (Variable) tuning p y S co d, secure a control action whose influence will intWO detectors ll Working upon resistances l2 crease with larger variations in this excitation Which e of a high and equal ehi d, a

. in quadrature, or will have a different effect for Coupler 0011 coupled to P t a d e ned 20 a given departure of the frequency. If the t ned to insure excitation in quadrature and which in i it upplying thi quadrature excitaticn is the present instance is applied to the rejector not particularly satisfactory, the excitation may (Suppressor grid) o e p ntode- Vary only small amount, t t effect never- 'It will be noted that the circuit of the said grid theless can be made very variable if a slight varicomprises in addition to t e c upling coil IS, the

ation of instantaneous frequency results in an tWO resistances from a to and e si appreciable change in the biasing of the grid battery upon hi th same i impressed, and this is It will also be noticed that the resistance [2 possible to do by means of a difierential system. connected at b as a matter of act, shunted In brief, the invention as applied to a selfby p y and the second resistance I2 30 generating or self-oscillatory circuit organization will be shunted the same Way y e p c ty i t in creating supplementary excitation These capacities are intended to insure filtering which is essentially in quadrature relation to the of the detected-radio frequency. xamining the normal or main excitation, and in, applying the properties of this part of the circuit organization 5 same to a control grid Whose bias varies'very which basically is known in the art, t Will he markedly it t frequency understood that the direct current voltage tapped Fi 1 a 2 ll t t by way of exampl two between a and b is zero when the circuit 9, 9', embodiments of the present invention. Fig. 3 m is strictly tuned t the freq ency, and this is a vector diagram given to aid in an underby Virtue 0f the fact that the radio frequency 40 standing of the invention a potentials applied to the detectors are equal as 40 Referring to this Fig. 1; there .i h n an rcsultants of a common voltage furnished by the oscillator circuit including a pentode vacuum inductance 2 and a Voltage which s i quad ature tube I, having in circuit therewith an oscillatory and s p ss the e als of the condenser circuit comprising an inductance 1 2 and a Ill as a result of mutual inductance existing beshunt tuning condenser 3, this oscillatory circuit tween 0011s 2 and The potentials i phase 5 being adapted to maintain oscillations. Assoquadrature a On t e One a d, the p n al ciated with the control first grid of tube I there of inductance 2 (or of the small inductance 9 is a leak resistance 4. The first grid and the coupled to a d on th th r hand, t p t plate of the vacuum tube are respectively coupled tial between the center point B of the small into the oscillatory circuit 2, 3 by means of conductance 9 and the point of junction of one of 50 densersfi and 6. The condenser 6, in effect, is a the large inductances 9' or 9" and the condenser blocking condenser. A plate blocking inductance l 0, labeled 0 or D (or the potential in inductance coil 1 is provided between the plate of the vacuum l3 coupled to the large inductance 9"). Under l and the positive terminal of a source of polarizthese conditions, the battery l4 alone will govern ing potential as shown. 1 the biasing of the suppressor grid, and the ex- 55 citation in quadrature set up at it has a definite effect. However, it will at once be seen that if the frequency varies, then the potential across the terminals of H] is no longer in quadrature relationship to that across the terminals of 2, and a direct current potential will arise between or across a and b; this potential being added to or deducted from that of the battery I4 will alter the bias or polarization of the suppressor grid and as a consequence the effect of the excitation set up across the terminals of I5, even if the amplitude of the latter may be taken to have remained unchanged. Hence, all that is necessary is to choose a convenient sense for the mutual inductance in order to insure the desired action. It will be noted thatand this is an essential feature of the inventionthe action and thus the stability of the frequency may be raised, without affecting the quality of the circuit 9, 9', 9" by relaxing or loosening the coupling between 9" and I3 and increasing the amplitudes set up across the terminals of the detectors. Indeed, under these conditions there will be the same alternating amplitude at l3, but the variable bias between a and b will vary at a much faster rate with departure of the frequency.

The appearance of unequal currents in resistances a and b is due to the dephasing which is produced at tuning of circuits 9, l0 and 2, 3; the unrectified potentials, applied between the common point of resistances a and b and the respective terminals of condenser Ill, are indeed normally expressed by equal vectors AC and AD shown in Fig. 3, potential AB being furnished by inductance 2, potentials in quadrature BC or BDbeing derived between the center point of the small inductance 9, and each respective terminal common to condenser Ill and to a large inductance 9' or 9".

When detuned, vectors BC and BD become BC and BD', they continue to be equal and opposed, and their amplitude changes very little in regard to vectors'BC and BD. However, the resultants AC and AD become clearly different, and the rectified potentials applied to the terminals of resistances a and b are proportional to the amplitudes of said vectors which explains a resulting term which modifies the continuous bias on the suppressor grid.

In what precedes, the implicit assumption has been made that the slope of the characteristic of the plate current as a function of the potential of the suppressor grid is not linear; hence, it will be desirable to make the latter of a Variable pitch. It would also be feasible to increase the control action by incorporating in the circuit organization a small supplementary variable slope (,u) tube designed to amplify the quadrature ex, citation. What thus results is a circuit scheme of the kind shown in Fig. 2. Also, in this case the oscillator tube is of the pentode type.

In Fig. 2 the same reference letters are used for identical elements as in Fig. 1. The voltage across the terminals of I3 is amplified by the variablet tube it instead of being applied directly to a control electrode of tube I. In this particularly simple embodiment, the amplified potential serves to control the pentode by connecting the plate of tube IS with the screen of tube l and a suitable positive potential through a blocking inductance coil I1.

What I claim is:

1. An oscillation generator comprising an electron tube having a cathode, an anode, first and second grid electrodes, a tuned circuit coupled to said cathode, anode and first grid electrode, and means for producing an oscillatory voltage in said tuned circuit, said means comprising means for applying an excitation voltage derived from said tuned circuit to said first grid electrode of the tube for sustaining oscillations, means for applying a second excitation voltage derived from said tuned circuit to said second grid electrode of the tube, means for dephasing said second excitation voltage substantially in quadrature with respect to said first excitation voltage, means for combining voltages proportional to said two excitation voltages to produce two direct current voltages, one responsive to the vector sum and one responsive to the vector difference of said proportional voltages, and means for applying the resultant of said two direct current voltages to said second grid, whereby the frequency of said tuned circuit is stabilized.

2. An oscillation generator comprising an electron tube having a cathode, an anode, first and second grid electrodes, a main tuned circuit coupled to said cathode and one of the said grid electrodes, an auxiliary tuned circuit having two sides and coupled with said main tuned circuit so as to be driven thereby, means for combining voltage from the main tuned circuit and voltage on one side of the auxiliary tuned circuit, and means for rectifying said combined voltage,

means for combining voltage from the main 4 tuned circuit and voltage on the other side of the auxiliary circuit, and means for rectifying said last combined voltage, means for combining said rectified voltages in opposing relation to produce a resultant voltage, and means for applying to said other grid said resultant voltage and a bias ing voltage and also a voltage in phase with the voltge across said auxiliary circuit, whereby departures of the generated frequency from the normal operating frequency controls the magnitude and polarity of said resultant voltage in such sense as to oppose said departures of frequency.

3. An oscillation generator comprising an electron discharge device having a cathode, an anode and a grid, means for producing oscillations including sources of potential for energizing said electrodes and a tuned circuit composed of inductance and capacitance, means for deriving from said tuned circuit a voltage which increases with frequency and another voltage which decreases with increase in frequency, separate means for rectifying said voltages, an apertured electrode in said tube for affecting the frequency of said oscillations, and means for combining the rectified voltages in opposition to each other and for applying the resultant to said apertured electrode, whereby the frequency of oscillations produced by said generator is stabilized without dependence upon amplitude Variations.

4. An oscillation generator comprising an electron tube having a cathode, anode, a control grid, a screen grid and a suppressor grid, a tuned circuit coupled to said anode, cathode and control grid, means for producing an oscillatory voltage in said tuned circuit and for applying to the control grid an excitation voltage derived from said tuned circuit for maintaining oscillations, biasing means in said suppressor grid circuit, means for applying a second excitation voltage to said suppressor grid circuit means for dephasing said second excitation voltage substantially in quadrature with respect to said first excitation voltage, means for combining voltages proportional to said excitation voltages to produce two direct current voltages, one responsive to the vector sum and one responsive to the vector difference of said proportional voltages, and means for applying the resultant of said two direct current voltages to said suppressor grid, whereby the frequency of said tuned circuit is stabilized.

An oscillation generator as claimed in claim 4, wherein the suppressor grid has a variable pitch.

6. An oscillation generator comprising an electron tube having a cathode, an anode, a control grid and a screen grid, a tuned circuit coupled to said cathode and control grid, means for producing an oscillatory Voltage in said tuned circuit and for applying to the control grid an excitation voltage derived from said tuned circuit for maintaining oscillations, biasing means in said screen grid circuit, means for applying a second excitation voltage to said screen grid circuit, means for dephasing said second excitation voltage substantially in quadrature with respect to said first excitation voltage, and means for combining voltages proportional to said two excitation voltages to produce two direct current voltages, one responsive to the vector sum and one responsive to the vector difierenc-e of said proportional voltages, and means for applying the resultant of said two direct current voltages to said screen grid, whereby the frequency of said tuned circuit is stabilized.

7. An oscillation generator comprising an electron tube having a cathode, an anode, a control grid and a screen grid, a tuned circuit coupled to the cathode and control grid of said tube, means for producing an oscillatory voltage in said tuned circuit and applying to the control grid a voltage excitation in dependence upon the voltage of said tun-ed circuit for maintaining oscillations, a variable mu valve relay having its anode-cathode space connected between said screen grid and cathode, biasing means in the input circuit of said variable mu valve, means in series with said biasing means for applying a second excitation voltage to said input circuit, means for dephasing said second excitation voltage substantially in quadrature with respect to said first excitation, and means responsive to the amplitude of the vector sum of said first and second excitation voltages for varying the magnitude of the voltage developed by said biasing means for stabilizing said tuned circuit frequency.

8. An oscillation generator comprising an electron discharge device having a cathode, an anode and a grid, means for producing oscillations including sources of potential for energizing said electrodes and a tuned circuit composed of inductance and capacitance, means for deriving from said tuned circuit a voltage which increases with frequency and another voltage which decreases with increase in frequency, separate means for rectifying such voltages, an apertured electrode in said tube for affecting the frequency of said oscillations, and means for combining the rectified voltages in opposition to each other for applying the resultant to said apertured electrode, a further means for applying to said apertured electrode the voltage derived from said tuned circuit and in quadrature with the voltage across said tuned circuit, whereby the frequency of oscillations produced by said generator is stabilized without dependence upon amplitude variations.

HENRI CHIREIX. 

